VirtualBox is a general-purpose full virtualizer for x86 hardware. Targeted at server, desktop and embedded use, it is now the only professional-quality virtualization solution that is also Open Source Software.

Some of the features of VirtualBox are:

Modularity. VirtualBox has an extremely modular design with well-defined internal programming interfaces and a client/server design. This makes it easy to control it from several interfaces at once: for example, you can start a virtual machine in a typical virtual machine GUI and then control that machine from the command line, or possibly remotely. VirtualBox also comes with a full Software Development Kit: even though it is Open Source Software, you don't have to hack the source to write a new interface for VirtualBox.

Virtual machine descriptions in XML. The configuration settings of virtual machines are stored entirely in XML and are independent of the local machines. Virtual machine definitions can therefore easily be ported to other computers.

# The following major new features were added:* Improved Windows 8 support, in particular many 3D-related fixes* GUI: VM groups * GUI: expert mode for wizards* GUI: allow to alter some settings during runtime* Support for up to 36 network cards, in combination with an ICH9 chipset configuration * Resource control: added support for limiting network IO bandwidth; see Section 6.9, “Limiting bandwidth for network I/O”* Added possibility to start VMs during system boot on Linux, OS X and Solaris; see Section 9.24, “Starting virtual machines during system boot” * Added experimental support for Drag'n'drop from the host to Linux guests. Support for more guests and for guest-to-host is planned. * Added support for Host parallel port passthrough on Windows platform# In addition, the following items were fixed and/or added:* Mac OS X hosts: sign application and installer to avoid warnings on Mountain Lion* VMM: improved VM context switch performance for Intel CPUs using nested paging* VMM: added support for FlushByASID features of AMD CPUs (Bulldozer and newer)* VMM: fixed unreal mode handling on older CPUs with VT-x (gPXE, Solaris 7/8/9)* VMM: fixed MP tables fixes for I/O APIC interrupt routing relevant for ancient SMP guests (e.g. old OS/2 releases)* VMM: support recent VIA CPUs * GUI: network operations manager* GUI: allow taking screenshots of the current VM window content * GUI: allow automatically sorting of the VM list* GUI: allow starting of headless VMs from the GUI* GUI: allow reset, shutdown and poweroff from the Manager window* GUI: allow to globally limit the maximum screen resolution for guests* GUI: show the full medium part on hovering the list of recently used ISO images* GUI: do not create additional folders when a new machine has a separator character in its name * GUI: don't crash on terminate if the settings dialog is still open * Snapshots: fixed a crash when restoring an old snapshot when powering off a VM * Settings: sanitise the name of VM folders and settings file * Settings: allow to store the iSCSI initiator secret encrypted* E1000: 802.1q VLAN support * Storage: implemented burning of audio CDs in passthrough mode* Storage: implemented support for discarding unused image blocks through TRIM for SATA and IDE and UNMAP for SCSI when using VDI images* Storage: added support for QED images* Storage: added support for QCOW (full support for v1 and readonly support for v2 images)* Storage: added readonly support for VHDX images* Solaris additions: added support for X.org Server 1.11 and 1.12* Windows hosts: no need to recreate host-only adapters after a VirtualBox update* Windows hosts: updated toolchain; make the source code compatible to VC 2010 and enable some security-related compiler options